Textbook of normal histology: including an account of the development of the tissues and of the organs . todermic or entodermic tissue, exceptin those cases where the glands are formed inconnection with the parts of the genito-urinarytract derived entirely from the mesoderm. The first trace of the glands consists of acylindrical ingrowth of the epithelium intothe subjacent mesodermic tissue, both the tubularand the saccular glands alike starting as simpleepithelial processes. Where, however, the struct-ure is destined to become a gland of the racemosetype, the branching cords of epithelial ele
Textbook of normal histology: including an account of the development of the tissues and of the organs . todermic or entodermic tissue, exceptin those cases where the glands are formed inconnection with the parts of the genito-urinarytract derived entirely from the mesoderm. The first trace of the glands consists of acylindrical ingrowth of the epithelium intothe subjacent mesodermic tissue, both the tubularand the saccular glands alike starting as simpleepithelial processes. Where, however, the struct-ure is destined to become a gland of the racemosetype, the branching cords of epithelial elementsearly indicate the nature of the future gland asdistinguished from one of the compound tubularvariety ; since, in this case, the terminations ofthe epithelial masses soon become markedly ex-panded and club-shaped, from which dilatationsthe ultimate divisions or primary alveoli of the racemose glands areextended secondarily. The epithelial cords, at first solid, lateracquire a lumen which extends as far as the terminal compartmentsof the gland. Sometimes, as conspicuously instanced by the Developing salivarygland from fifteen-dayrabbit embryo. Theectodermic ingrowth hasdivided into secondarybranches which termi-nate in slightly expandedclub - shaped ends : e,epithelium of oral sur-face ; in, young connec-tive tissue of future tunicapropria into which theepithelium grows. MUCOUS MEMBRANES AND GLANDS. j^? the primary arrangement of the gland is modified by subsequentchanges to such a degree that the original plan of its structure isrecognized with difficulty. The sexual glands are so highly special-ized that in their development they deviate materially from the modeof the formation of the typical secretory organs. Ordinarily theelaborating glandular cells are ectodermic and entodermic in origin,while the basement-membranes and supporting tissues are meso-dermic. 144 NORMAL HISTOLOGY. CHAPTER X. THE DIGESTIVE TRACT. Fig. 172. THE MOUTH. The mucous membrane of the oral
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Keywords: ., bookauthorpiersolgeorgeageorgea, bookcentury1800, bookdecade1890
